Development aspects of optic nerve fiber growth will be examined in eye-grafted amphibians (axolotls) and birds (quail and chick), in order to learn more about factors controlling decussation, directional specificity, regenerative capacity, and establishment of terminations. Both afferent and efferent innervation of the eye and its associated structures will be studied. The methods used will include protargol silver-staining, methylene blue, and Golgi staining techniques, scanning and transmission electron microscopy, and autoradiography using tritiated proline as a label. Ganglion cells in the bird retina will be examined and classified according to their ability to survive section of their axons.